To develop serological tests for antibody to measles and other paramyxoviruses in the CSF and for increasing the specificity of recognition of mumps and parainfluenza virus antibody in the serum. To determine the incidence of specifically elevated CSF antibody against individual paramyxoviruses and herpesvirus in multiple sclerosis patients and controls. To test the correlation between history of paramyxoviruses and the development of multiple sclerosis in communities where infection with these viruses occurs during intense epidemics at prolonged internals.